The present invention concerns a method and apparatus for making curved hems about the periphery of respective openings in a moving web of fabric, such as a web of material employed in the manufacture of disposable diapers. The modern manufacture of items such as disposable diapers usually employs continuous moving webs of materials, such as non-woven fabrics, moving at high speeds, for example, linear speeds of 600 feet per minute. The high web speeds necessary for efficient manufacture make it difficult to form hems about openings cut in the web.